A Simplified Analysis Method of Permanent Magnet Homopolar Inductor Machine With 3-D Magnetic Field Distribution

Permanent magnet homopolar inductor machine (PMHIM) has received extensive attention in the field of flywheel energy storage system (FESS) due to its merits of simple structure, rotor flywheel integration, and high operation efficiency. However, its inherent 3-D flux density distribution results in a huge time cost in motor design and analysis. To improve the analysis and design efficiency, a simplified 2-D analysis method of the PMHIM is proposed in this article. The space overlay method of air-gap flux density and air-gap permeability is implemented, and the PMHIM can be equivalent to an equivalent machine (EM) with 2-D magnetic field distribution. The electromagnetic performance, including the effective air-gap flux density, flux linkage, back electromagnetic force (back EMF), torque, and so on, of the PMHIM can be well predicted by the EM. First, the mathematical model of the PMHIM is derived. Then, the EM of PMHIM is established, which reveals the mathematical relationship between the PMHIM and the EM. Finally, the rationality of EM is verified by finite element analysis (FEA) and experiment. The results show that the proposed method can accurately simulate the electromagnetic performance of PMHIM, which is beneficial to the rapid analysis and design of PMHIM.